I had a 4 month old hen die a couple days ago and I noticed one of my 7 weeks old has some of the same symptoms. I want to figure this out before I lose more. Both their necks seemed loose and they turn it almost 180 around to one side or it hangs low and they seem to have trouble walking, like their balance is off or perhaps they are dizzy. The pupils look too big and don't seem to change like they cannot focus on something. The older one also had these symptoms: Eyes half closed, lethargy, loss of appetite, diarrhea, and weight loss. Also, the young one I just noticed today is gasping like she's having trouble breathing which is what the older one was doing the day she died. A few nights ago, I spotted a rat (mother) with two young and I'm concerned they might have spread something. Does anyone know what this might be?